The objective of the Training Program in Infectious Diseases at Memorial Sloan Kettering Cancer Center is to provide post-doctoral research training to MD and MD/PhD fellows in the following areas: 1) Infectious disease pathogenesis; 2) Host defense against infection; 3) Translational studies of human immune defenses against infection; and 4) Clinical investigation of infectious diseases in immunocompromised hosts. The duration of training will be two years and six positions are requested, three for first year fellows and three for second year fellows. All six positions will be filled by clinicians who come to MSKCC for training in the subspecialty of Infectious Diseases. These fellows will enter the research-training program and be supported by this training grant for two years after the completion of their clinical training. The objectives of our training program are to train basic and clinical investigators for academic careers in the areas of host defense, microbial pathogenesis, infectious diseases diagnosis and immune-based anti-microbial therapy. This training program will provide a structured environment with intensive involvement of the Infectious Diseases and associated faculty in the training of fellows. Faculty participating on this training grant will provide mentorship in a range of research areas spanning from innate/adaptive immune responses to infectious pathogens to clinical studies of infections in allogeneic transplant patients. A core curriculum in clinical investigation is funded by an existing K-30 award entitled Clinical Research Methodology Curriculum at Memorial Sloan Kettering Cancer Center and provides didactic teaching in the design and completion of clinical studies. A curriculum of seminars, journal clubs, lab meetings and formal courses has been developed for fellows performing laboratory-based research. [unreadable] [unreadable]